have mentioned Steven Saylor and my fondness for stories of ancient Rome before; I also have a penchant for book series, especially longer series that move forward in time with character (as in the Sharpe novels by Ber Cornwell). This latest offering from Saylor fed both those Joneses.
As usual, Saylor's keen depiction of detail and historical authenticity carry the book. To read a Saylor novel is to immerse yourself in an ancient time that is at once strange and familiar; the author has a way of filtering the sometimes brutal sensibilities of the times through sympathetic characters, making them more understandable and a little more palatable to our modern tastes.
Plot is usually Saylor's downfall; his mysteries aren't always "play fair" and he often relies on coincidence to get Gordianus out of a tight spot - or has the hero come to the wrong conclusion, but things work out alright anyway. The young Finder seems to have a bit more agency and initiative, and most of his successes come from his own efforts. The characters are pretty much stock Saylor - interesting, but a bit flat. Like Harry Turtledove, Saylor seems to have a limited repertory company at his disposal, and the same types seem to pop up repeatedly.
Overall, the book spins a good yarn, with camel chases and secret hideouts and crocodiles and plucky boys and scheming chamberlains: all the things you might want in Ptolemaic Egyptian intrigue.